[swift-evolution] Change Request: Make myString.hasPrefix("") and myString.hasSuffix("") return true

[Tony Allevato]

On Wed, Jul 20, 2016 at 1:14 PM Guillaume Lessard via swift-evolution <
swift-evolution at swift.org> wrote:

>
> > On 20 juil. 2016, at 12:42, Michael Peternell via swift-evolution <
> swift-evolution at swift.org> wrote:
> >
> > +1
> > this should be a bugfix.
>
> First, NSString’s prefix function returns false for empty string
> parameters, and this would be a significant departure in behaviour.
>

It would be a significant correction in behavior.


> Second, while an empty string is technically a prefix to any other string,
> that is hardly ever an interesting answer; it is a trivial solution, just
> as y=0 is for y(x)=y’(x). It is easy to special-case if one really needs to
> consider the empty string.
>

On the contrary—I've written code in the past that expected this behavior
(because why wouldn't I? It's the correct behavior) and was quite surprised
when NSString's behavior resulted in a bug.

NSString being plain wrong here should not consign us to wrongness forever.
Every other mainstream language I use day-to-day implements this correctly,
and so should Swift.


>
> Cheers,
> Guillaume Lessard
>
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